High-weather-resistance and high-durability asphalt concrete and preparation method thereof

Abstract

This application discloses a high-weather-resistant and high-durability asphalt concrete and its preparation method. On one hand, this application provides a high-weather-resistant and high-durability asphalt concrete, wherein the weight proportions of its components include: 38-44 parts coarse aggregate, 18-24 parts fine aggregate, 8-12 parts ultrafine filler, 6-10 parts SBS modified asphalt, and 6-8 parts asphalt modifier; the weight proportions of the asphalt modifier include: 20-24 parts carboxymethyl chitosan microcapsules coated with aromatic oil repair agent, 6-10 parts waste rubber powder, 10-12 parts epoxy resin, 4-8 parts nano-silica, and 8-12 parts basalt short fibers. On the other hand, this application also provides a method for preparing the above-mentioned high-weather-resistant and high-durability asphalt concrete. This application has relatively low cost, can effectively improve low-temperature crack resistance and high-temperature rutting resistance, and has strong anti-aging properties and durability.

Description

Technical Field

[0001] This application relates to the field of building materials technology, and in particular to a high weather-resistant and high-durability asphalt concrete and its preparation method. Background Technology

[0002] Asphalt concrete is a building material composed of two materials with completely different properties (aggregate and asphalt). Due to its excellent impermeability, adaptability to deformation, and resistance to erosion, it is widely used in road construction. Compared with traditional gravel pavements, asphalt concrete pavements have the following advantages: improved vehicle stability and comfort during driving; increased driving speed, reduced fuel consumption, and significantly lower transportation costs; extended tire life, and reduced vehicle overhaul mileage. Currently, asphalt concrete is used for the vast majority of road paving in my country.

[0003] SBS modified asphalt is a new type of asphalt material made by uniformly dispersing a certain proportion of SBS modifier into base asphalt to form an SBS blend. It utilizes the excellent physical properties of SBS to modify the asphalt. Compared to traditional asphalt concrete, SBS asphalt concrete shows significant improvements in high and low temperature performance, fatigue resistance, and aging resistance. Currently, most asphalt concrete used in road construction and water conservancy projects in my country is SBS asphalt concrete.

[0004] However, the daily load on most urban roads far exceeds their design load. This leads to a large number of existing asphalt concrete pavements developing defects such as cracking, potholes, loosening, and rutting during their service life due to a combination of factors, severely impacting pavement performance and driving safety. Even pavements using SBS asphalt concrete experience aging during their service life due to overloading and other factors, resulting in road defects.

[0005] How to further improve the high and low temperature resistance and durability of asphalt concrete, so as to achieve a longer service life under high load conditions, is a problem that needs to be solved in this field. Summary of the Invention

[0006] In order to solve at least one of the above-mentioned technical problems, and to develop an asphalt concrete with relatively low cost, which can effectively improve low-temperature crack resistance and high-temperature rutting resistance, and has strong anti-aging properties and durability, this application provides a high weather-resistant and high-durability asphalt concrete and its preparation method.

[0007] On one hand, this application provides a high weather-resistant and high-durability asphalt concrete. The weight proportions of the components of the asphalt concrete include: 38-44 parts coarse aggregate, 18-24 parts fine aggregate, 8-12 parts ultrafine filler, 6-10 parts SBS modified asphalt, and 6-8 parts asphalt modifier. The weight proportions of the components of the asphalt modifier include: 20-24 parts carboxymethyl chitosan microcapsules coated with aromatic oil repair agent, 6-10 parts waste rubber powder, 10-12 parts epoxy resin, 4-8 parts nano silica, 8-12 parts basalt short fiber, 2-4 parts antioxidant, and 2-4 parts UV stabilizer. The weight proportions of the components of the aromatic oil repair agent include: 20-24 parts aromatic oil, 8-12 parts epoxy resin, and 6-10 parts epoxidized soybean oil.

[0008] Optionally, the coarse aggregate is selected from basalt crushed stone with a particle size of 4-6 mm.

[0009] Optionally, the fine aggregate is manufactured sand with a particle size of 1-2 mm.

[0010] Optionally, the ultrafine filler is a compound mixture of mineral powder and steel slag with a particle size of less than 0.5 mm, and the ratio of mineral powder to steel slag is 1.5 to 2:1.

[0011] Optionally, the carboxymethyl chitosan microcapsules coated with the aromatic oil repair agent have a coating rate of 30-40%.

[0012] Optionally, the preparation of the carboxymethyl chitosan microcapsules coated with the aromatic oil repair agent adopts the following steps:

[0013] Sa, accurately weigh carboxymethyl chitosan and aromatic oil according to the coating ratio;

[0014] Sb, Dissolve carboxymethyl chitosan in water to prepare an aqueous solution with a concentration of 1~2.5%;

[0015] Sc. Mix all components of the aromatic oil repair agent evenly to form an oil phase. Pour the oil phase into the aqueous solution, add Tween 80 emulsifier, stir and homogenize at 4000~4500 rpm for 4~8 min to obtain a homogeneous emulsion.

[0016] Sd. Take a ferric chloride solution with a concentration of 2-2.5% and a volume of 80-100% of the homogeneous emulsion. Slowly pour the homogeneous emulsion obtained in step Sc into the ferric chloride solution. Stir and react for more than 1 hour at a speed of 400-500 rpm. Filter out the solid matter and dry it to obtain carboxymethyl chitosan microcapsules coated with aromatic oil repair agent.

[0017] Optionally, the waste rubber powder is selected from waste tire rubber powder.

[0018] Optionally, the epoxy resin is selected as AG-70 low-viscosity tetrafunctional epoxy resin.

[0019] Optionally, the basalt short fibers are selected with a diameter of 20~50μm and a length of 0.5~1mm.

[0020] On the other hand, this application also provides a method for preparing the above-mentioned high weather resistance and high durability asphalt concrete, including the following steps:

[0021] S1. Thoroughly mix coarse aggregate, fine aggregate and ultrafine filler, and preheat to 200~220℃;

[0022] S2. Heat the SBS modified asphalt to 165~170℃, then add the asphalt modifier, and maintain the temperature at 165~170℃ while stirring and mixing thoroughly.

[0023] S3. Mix the mixtures from steps S1 and S2, heat to 180~185℃, and stir thoroughly to obtain high weather resistance and high durability asphalt concrete.

[0024] In summary, the present invention has at least one of the following beneficial technical effects:

[0025] 1. This application uses coarse aggregate, fine aggregate and ultrafine filler as the main materials, and mixes them in a specific ratio to form a relatively effective gradation, which can greatly improve the strength of asphalt concrete.

[0026] 2. This application uses SBS modified asphalt as the asphalt material and adds a specific ratio of asphalt modifier, which can effectively improve the high and low temperature performance and weather resistance of asphalt concrete. The addition of epoxy resin can form a network cross-linked structure with SBS modified asphalt. Combined with the addition of waste rubber powder, it can greatly improve the toughness of asphalt and its high temperature rutting resistance. The addition of basalt short fibers can significantly improve the low temperature crack resistance of asphalt concrete. The above asphalt modifiers and SBS modified asphalt can significantly improve the weather resistance of asphalt concrete.

[0027] 3. The asphalt modifier of this application contains carboxymethyl chitosan microcapsules coated with aromatic oil repair agent. The carboxyl active groups of the outer carboxymethyl chitosan can form a network cross-linked structure with SBS modified asphalt. The aromatic oil coated with it can be slowly released under pressure after the SBS modified asphalt ages, forming a lasting repair on the asphalt and effectively improving the durability of asphalt concrete. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] This application provides a high weather-resistant and high-durability asphalt concrete. The asphalt concrete comprises the following components in the following weight proportions: 38-44 parts coarse aggregate, 18-24 parts fine aggregate, 8-12 parts ultrafine filler, 6-10 parts SBS modified asphalt, and 6-8 parts asphalt modifier. The asphalt modifier comprises the following components in the following weight proportions: 20-24 parts carboxymethyl chitosan microcapsules coated with aromatic oil repair agent, 6-10 parts waste rubber powder, 10-12 parts epoxy resin, 4-8 parts nano silica, 8-12 parts basalt short fiber, 2-4 parts antioxidant, and 2-4 parts UV stabilizer. The aromatic oil repair agent comprises the following components in the following weight proportions: 20-24 parts aromatic oil, 8-12 parts epoxy resin, and 6-10 parts epoxidized soybean oil.

[0030] The method for preparing the above-mentioned high weather-resistant and high-durability asphalt concrete of this application includes the following steps:

[0031] S1. Thoroughly mix coarse aggregate, fine aggregate and ultrafine filler, and preheat to 205~210℃;

[0032] S2. Heat the SBS modified asphalt to 165~170℃, then add the asphalt modifier, and maintain the temperature at 165~170℃ while stirring and mixing thoroughly.

[0033] S3. Mix the mixtures from steps S1 and S2, heat to 180~185℃, and stir thoroughly to obtain high weather resistance and high durability asphalt concrete. The discharge temperature is controlled at 160~165℃.

[0034] To address the problems existing in the prior art, this application redesigns the mix proportions of asphalt concrete, using coarse aggregate, fine aggregate, and ultrafine filler as the main materials to form an effective gradation. Furthermore, this application designs an asphalt modifier with a specific ratio that, in addition to toughening and strengthening, also acts as a slow-release asphalt repair agent. The above design can effectively improve the various properties and durability of asphalt concrete.

[0035] The following are preparation examples and embodiments of this application.

[0036] All the main raw materials used in the embodiments of this application are commercially available.

[0037] Among them, SBS modified asphalt, PG 76-22 type modified asphalt, was purchased from SK Corporation; carboxymethyl chitosan was purchased from Wuhan Jiyesheng Chemical Co., Ltd.; aromatic oil (aromatic content ≥55%) was purchased from Sinopec; epoxy resin, AG-70 low viscosity tetrafunctional epoxy resin was purchased from BASF; nano silica, oleophilic type, particle size 150~400nm, was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; basalt short fiber was purchased from Sichuan Qianyi Composite Materials Co., Ltd.; antioxidant, antioxidant 1010 was purchased from Shanghai Longsheng Chemical Co., Ltd.; UV stabilizer, SEBS FG1924G, was purchased from Kraton Chemical Co., Ltd.

[0038] The preparation of the carboxymethyl chitosan microcapsules coated with aromatic oil repair agent in this application example adopts the following steps:

[0039] Sa, accurately weigh carboxymethyl chitosan and aromatic oil according to the coating ratio (e.g., if the coating rate is 30%, that is, aromatic oil accounts for 30% of the total mass of the microcapsules, and carboxymethyl chitosan and aromatic oil are weighed in a mass ratio of 7:3).

[0040] Sb, Dissolve carboxymethyl chitosan in water to prepare a 2% aqueous solution;

[0041] Sc. Mix the components of the aromatic oil repair agent evenly to form an oil phase. Pour the oil phase into the aqueous solution, add Tween 80 emulsifier, stir at 4000 rpm and homogenize for 5 min to obtain a homogeneous emulsion.

[0042] Sd. Take an equal volume of 2% ferric chloride solution to the homogenized emulsion. Slowly pour the homogenized emulsion obtained in step Sc into the ferric chloride solution. Stir and react at 450 rpm for 1 hour. Filter out the solid and dry it to obtain carboxymethyl chitosan microcapsules coated with aromatic oil repair agent.

[0043] Testing showed that the carboxymethyl chitosan microcapsules coated with aromatic oil repair agents prepared by the above method had a coating success rate of 99.4% (calculated based on the remaining amount of oil phase), and the microcapsule particle size was 10~60μm.

[0044] Preparation Example 1

[0045] The asphalt modifier of this preparation example has the following component weight ratios: 20 parts of carboxymethyl chitosan microcapsules coated with aromatic oil repair agent (coating rate 30%), 10 parts of waste tire rubber powder, 12 parts of epoxy resin, 4 parts of nano silica, 8 parts of basalt short fibers (diameter 80~120μm, length 1~2mm), 2 parts of antioxidant, and 2 parts of UV stabilizer; wherein, the aromatic oil repair agent has the following component weight ratios: 20 parts of aromatic oil, 12 parts of epoxy resin, and 10 parts of epoxidized soybean oil.

[0046] The asphalt modifier in this preparation example is prepared by thoroughly mixing the components.

[0047] Preparation Example 2

[0048] The asphalt modifier of this preparation example has the following component weight ratios: 24 parts of carboxymethyl chitosan microcapsules coated with aromatic oil repair agent (coating rate 30%), 6 parts of waste tire rubber powder, 10 parts of epoxy resin, 8 parts of nano silica, 12 parts of basalt short fibers (diameter 80~120μm, length 1~2mm), 4 parts of antioxidant, and 4 parts of UV stabilizer; wherein, the aromatic oil repair agent has the following component weight ratios: 24 parts of aromatic oil, 8 parts of epoxy resin, and 6 parts of epoxidized soybean oil.

[0049] The asphalt modifier in this preparation example is prepared by thoroughly mixing the components.

[0050] Preparation Example 3

[0051] The asphalt modifier of this preparation example has the following component weight ratios: 22 parts of carboxymethyl chitosan microcapsules coated with aromatic oil repair agent (coating rate 30%), 8 parts of waste tire rubber powder, 12 parts of epoxy resin, 6 parts of nano silica, 10 parts of basalt short fibers (diameter 80~120μm, length 1~2mm), 3 parts of antioxidant, and 3 parts of UV stabilizer; wherein, the aromatic oil repair agent has the following component weight ratios: 22 parts of aromatic oil, 10 parts of epoxy resin, and 8 parts of epoxidized soybean oil.

[0052] The asphalt modifier in this preparation example is prepared by thoroughly mixing the components.

[0053] Preparation Example 4

[0054] The difference between this preparation example and preparation example 3 is that the encapsulation rate of the carboxymethyl chitosan microcapsules encapsulating the aromatic oil repair agent is 35%.

[0055] Preparation Example 5

[0056] The difference between this preparation example and preparation example 3 is that the carboxymethyl chitosan microcapsules coated with the aromatic oil repair agent have a coating rate of 40%.

[0057] Preparation Example 6

[0058] The difference between this preparation example and preparation example 5 is that the basalt short fibers selected are short fibers with a diameter of 5~20μm and a length of 0.1~0.5mm.

[0059] Preparation Example 7

[0060] The difference between this preparation example and preparation example 5 is that the basalt short fibers used are short fibers with a diameter of 20~50μm and a length of 0.5~1mm.

[0061] The high weather-resistant and high-durability asphalt concrete in the embodiments of this application are all prepared using the following method, including the following steps:

[0062] S1. Thoroughly mix coarse aggregate, fine aggregate and ultrafine filler, and preheat to 205℃;

[0063] S2. Heat the SBS modified asphalt to 165~170℃, then add the asphalt modifier, and maintain the temperature at 165~170℃ while stirring and mixing thoroughly.

[0064] S3. Add the mixture from steps S1 and S2 into a mixing pot, heat to 180~185℃, and mix thoroughly to obtain high weather resistance and high durability asphalt concrete; then cool to 160~165℃ and maintain the temperature for discharge and paving.

[0065] Example 1

[0066] The weight proportions of each component in the asphalt concrete of this embodiment include: 38 parts coarse aggregate, 24 parts fine aggregate, 12 parts ultrafine filler, 6 parts SBS modified asphalt, and 6 parts asphalt modifier.

[0067] The coarse aggregate is selected from screened gravel with a particle size of 4-6 mm, the fine aggregate is selected from yellow sand with a particle size of 1-2 mm, the ultrafine filler is selected from mineral powder with a particle size of 0.1-0.5 mm, and the asphalt modifier is selected from the product of Preparation Example 1.

[0068] Example 2

[0069] The weight proportions of each component in the asphalt concrete of this embodiment include: 44 parts coarse aggregate, 18 parts fine aggregate, 8 parts ultrafine filler, 10 parts SBS modified asphalt, and 8 parts asphalt modifier.

[0070] The coarse aggregate is selected from screened gravel with a particle size of 4-6 mm, the fine aggregate is selected from yellow sand with a particle size of 1-2 mm, the ultrafine filler is selected from mineral powder with a particle size of 0.1-0.5 mm, and the asphalt modifier is selected from the product of Preparation Example 1.

[0071] Example 3

[0072] The weight proportions of each component in the asphalt concrete of this embodiment include: 42 parts coarse aggregate, 21 parts fine aggregate, 9 parts ultrafine filler, 9 parts SBS modified asphalt, and 7.2 parts asphalt modifier.

[0073] The coarse aggregate is selected from screened gravel with a particle size of 4-6 mm, the fine aggregate is selected from yellow sand with a particle size of 1-2 mm, the ultrafine filler is selected from mineral powder with a particle size of 0.1-0.5 mm, and the asphalt modifier is selected from the product of Preparation Example 1.

[0074] Example 4

[0075] The difference between this embodiment and Embodiment 3 is that the coarse aggregate is basalt crushed stone with a particle size of 4-6mm, and the fine aggregate is manufactured sand with a particle size of 1-2mm.

[0076] Example 5

[0077] The difference between this embodiment and embodiment 4 is that the ultrafine filler is a compound mixture of mineral powder and steel slag with a particle size of 0.1~0.5mm, and the ratio of mineral powder to steel slag is 1.5:1.

[0078] Example 6

[0079] The difference between this embodiment and embodiment 4 is that the ultrafine filler is a compound mixture of mineral powder and steel slag with a particle size of 0.1~0.5mm, and the ratio of mineral powder to steel slag is 2:1.

[0080] Example 7

[0081] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product of Preparation Example 2.

[0082] Example 8

[0083] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product of Preparation Example 3.

[0084] Example 9

[0085] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product from Preparation Example 4.

[0086] Example 10

[0087] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product of Preparation Example 5.

[0088] Example 11

[0089] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product from Preparation Example 6.

[0090] Example 12

[0091] The difference between this embodiment and Example 5 is that the asphalt modifier used is the product of Preparation Example 7.

[0092] Comparative Example 1

[0093] This application adopts Example 14 of Chinese Invention Patent No. CN114804726A, entitled "An EME-14 High Modulus Asphalt Concrete and Its Preparation Method Thereof", as Comparative Example 1.

[0094] Comparative Example 2

[0095] The difference between this comparative example and Example 12 is that the carboxymethyl chitosan microcapsules coated with aromatic oil repair agent are replaced with equal amounts of AG-70 low-viscosity tetrafunctional epoxy resin and waste tire rubber powder. The weight ratio of AG-70 low-viscosity tetrafunctional epoxy resin to waste tire rubber powder is 1:1.

[0096] Comparative Example 3

[0097] The difference between this comparative example and Example 12 is that, in the aromatic oil repair agent, an equal amount of epoxidized soybean oil is used to replace the epoxy resin.

[0098] Comparative Example 4

[0099] The difference between this comparative example and Example 12 is that, in the aromatic oil repair agent, an equal amount of aromatic oil is used to replace epoxidized soybean oil.

[0100] Comparative Example 5

[0101] The difference between this comparative example and Example 12 is that basalt short fibers are replaced with an equal amount and specification of polypropylene short fibers.

[0102] Comparative Example 6

[0103] The difference between this comparative example and Example 12 is that no ultrafine filler was added.

[0104] The asphalt concrete of Examples 1 to 12 and Comparative Examples 1 to 6 of this application were tested for relevant properties, including high-temperature rutting resistance, low-temperature crack resistance, aging resistance and durability.

[0105] Among them, dynamic stability was determined in accordance with JTGE20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering", with results measured at 25℃ and 45℃ respectively.

[0106] Freeze-thaw splitting residual strength ratio: determined according to JTJ052-2000 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering";

[0107] Aging: The aging process was carried out according to the long-term aging method in the accelerated aging method of hot-mix asphalt mixture in JTGE20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering";

[0108] Fatigue life: The test was conducted according to the electric bending fatigue test in JTGE20-2011 "Test Procedures for Asphalt and Asphalt Mixtures in Highway Engineering"; the specific test parameters are as follows: test temperature: 25℃; loading waveform: Haversine; loading frequency: 10Hz; specimen size: 385mmX65mmX50mm; the specimen was considered to have reached fatigue failure when the stiffness modulus of the specimen decreased to 50% of the initial stiffness modulus; the number of cyclic loading cycles for initial fatigue failure and the number of cyclic loading cycles for fatigue failure after aging were tested for the asphalt concrete specimens respectively.

[0109] The test results are shown in Tables 1 and 2 below.

[0110] Table 1. Data on the cold and hot performance of asphalt concrete

[0111]

[0112] Table 2. Data on the Durability Test of Asphalt Concrete

[0113]

[0114] As can be seen from the data in Tables 1 and 2, the high-temperature resistance and low-temperature resistance of the asphalt concrete prepared by Examples 1-12 of this application after using aggregates with specific gradations and specific asphalt modifiers are significantly improved compared with Comparative Examples 1 and 6. It is evident that the solution of this application can effectively improve the high-temperature resistance and low-temperature resistance of asphalt concrete. In addition, the fatigue life and fatigue life after aging of Examples 1-12 of this application are also significantly better than those of Comparative Example 1, and the fatigue life and fatigue life after aging of Example 12 are also significantly better than those of Comparative Examples 2-6. It is evident that the solution of this application can greatly improve the aging resistance and durability of asphalt concrete.

[0115] Comparing the data from Examples 1-12 in Tables 1 and 2, it can be seen that after optimizing the mix proportions of asphalt concrete, the gradation was further optimized, and the various properties of the concrete were further improved. Furthermore, after optimizing the selection of coarse aggregate, fine aggregate, and ultrafine filler, the various properties of the concrete were further improved. Comparing the data from Examples 5 and 7-12, it can be seen that after optimizing the mix proportions of the asphalt modifier and the specifications of the basalt short fibers, the various properties of the concrete were further improved. In particular, after optimizing the coating rate of the carboxymethyl chitosan microcapsules coated with the aromatic oil repair agent, the durability and aging resistance of the concrete were significantly improved. The applicant conducted relevant experiments on the coating rate. When the coating rate exceeded 40%, the durability and aging resistance of the concrete decreased, and when the coating rate exceeded 54%, the decrease was very significant. The applicant speculates that an excessively high coating rate will cause the microcapsules to rupture too quickly and release the repair agent, thereby affecting the durability and aging resistance of the concrete.

[0116] Comparing the data in Tables 1 and 2 between Example 12 and Comparative Examples 2-6, it can be seen that the carboxymethyl chitosan microcapsules coated with aromatic oil repair agent used in this application can greatly improve the durability and aging resistance of concrete. After aging asphalt concrete is subjected to load, the microcapsules release the repair agent due to increased pressure, thus repairing the aged asphalt concrete and effectively extending its service life. Furthermore, the specific composition and ratio of the repair agent used in this application can greatly improve the repair effect and further extend the service life of the concrete. In addition, the use of basalt short fibers of specific specifications in this application has good skeletal strength and weather resistance, which can greatly improve the high-temperature and low-temperature resistance of concrete.

[0117] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A type of high weather-resistant and high-durability asphalt concrete, characterized in that, The weight proportions of the components in the asphalt concrete include: 38-44 parts coarse aggregate, 18-24 parts fine aggregate, 8-12 parts ultrafine filler, 6-10 parts SBS modified asphalt, and 6-8 parts asphalt modifier; the weight proportions of the components in the asphalt modifier include: 20-24 parts carboxymethyl chitosan microcapsules coated with aromatic oil repair agent, 6-10 parts waste rubber powder, 10-12 parts epoxy resin, 4-8 parts nano silica, 8-12 parts basalt short fiber, 2-4 parts antioxidant, and 2-4 parts UV stabilizer; the weight proportions of the components in the aromatic oil repair agent include: 20-24 parts aromatic oil, 8-12 parts epoxy resin, and 6-10 parts epoxidized soybean oil.

2. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The coarse aggregate is selected from basalt crushed stone with a particle size of 4-6 mm.

3. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The fine aggregate is manufactured sand with a particle size of 1-2 mm.

4. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The ultrafine filler is a mixture of mineral powder and steel slag with a particle size of less than 0.5 mm, and the ratio of mineral powder to steel slag is 1.5~2:

1.

5. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The carboxymethyl chitosan microcapsules used to coat the aromatic oil repair agent have a coating rate of 30-40%.

6. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The preparation of the carboxymethyl chitosan microcapsules coated with the aromatic oil repair agent is carried out using the following steps: Sa, accurately weigh carboxymethyl chitosan and aromatic oil according to the coating ratio; Sb, Dissolve carboxymethyl chitosan in water to prepare an aqueous solution with a concentration of 1~2.5%; Sc. Mix all components of the aromatic oil repair agent evenly to form an oil phase. Pour the oil phase into the aqueous solution, add Tween 80 emulsifier, stir and homogenize at 4000~4500 rpm for 4~8 min to obtain a homogeneous emulsion. Sd. Take a ferric chloride solution with a concentration of 2-2.5% and a volume of 80-100% of the homogeneous emulsion. Slowly pour the homogeneous emulsion obtained in step Sc into the ferric chloride solution. Stir and react for more than 1 hour at a speed of 400-500 rpm. Filter out the solid matter and dry it to obtain carboxymethyl chitosan microcapsules coated with aromatic oil repair agent.

7. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The waste rubber powder is selected from waste tire rubber powder.

8. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The epoxy resin used is AG-70 low-viscosity tetrafunctional epoxy resin.

9. The high weather resistance and high durability asphalt concrete according to claim 1, characterized in that, The basalt short fibers are selected with a diameter of 20~50μm and a length of 0.5~1mm.

10. A method for preparing high weather-resistant and high-durability asphalt concrete as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Thoroughly mix coarse aggregate, fine aggregate and ultrafine filler, and preheat to 205~210℃; S2. Heat the SBS modified asphalt to 165~170℃, then add the asphalt modifier, and maintain the temperature at 165~170℃ while stirring and mixing thoroughly. S3. Mix the mixtures from steps S1 and S2, heat to 180~185℃, and stir thoroughly to obtain high weather resistance and high durability asphalt concrete.

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